Few solutions hold as much potential to scale sustainable aviation fuel as SAF Book & Claim registries. The concept is straightforward: allow anyone, anywhere, to purchase credits that cover the SAF price premium in exchange for claiming its environmental benefits, while letting the fuel flow to or be transported to the most efficient distribution points.
However, the world is not yet ready to depend on SAF Book & Claim to drive SAF demand. A fragmented landscape of registries, limited interoperability, unclear emissions accounting, and regulatory hurdles are just a few of the challenges that SAF Book & Claim programs face. This briefing explores these key barriers, and the ongoing efforts to address them, and offers a glimpse into IATA's upcoming SAF registry – a soon-to-launch initiative supported by airlines.
SAF Book & Claim registries
The possibility of using Book & Claim Chain of Custody (CoC) systems to trade the environmental benefits of SAF separately from its physical volume has been a topic of discussion for well over a decade. However, efforts to develop accompanying methodologies and market-ready platforms only made meaningful progress in the past five years. Voluntary corporate demand for air travel emission insets based on SAF has been the main driver of that progress, with several large corporates pioneering SAF Book and Claim.
The leading SAF Book & Claim registries include:
- RSB Book & Claim Registry: The Roundtable for Sustainable Biomaterials (RSB) launched its Book & Claim Registry in November 2023, facilitating the tracking of sustainability attributes derived from SAF and other renewable fuels in the future. The registry is built on the RSB framework and reached 100 retirement statements representing 3,000 tonnes of SAF in September 2024.
- RMI’s SAF-c registry: Jointly founded with the Sustainable Aviation Buyers Alliance (SABA) and the Environmental Defense Fund (EDF), RMI’s SAF-c registry launched in December 2023. As of 18th March 2025, 90 retirements have been logged by the registry by end users such as Morgan Stanley and Microsoft.
- Avelia registry: Launched jointly by Shell, Accenture, and American Express Global Business Travel (Amex GBT) in June 2022, Avelia is one of the first blockchain-powered SAF solutions. The platform boasts one of the highest numbers of retirements to date (881 as of 18th March 2025). From June 2022 to May 2024, 10 million gallons of SAF (30,280 tonnes) were supported by the platform.
- 4AIR’s Assure registry: Launched in May 2023 by 4AIR, a company that helps offset emissions. At launch, Assure was seeking harmonisation with the RSB Book & Claim Registry.
- Chooose & SkyNRG: SkyNRG – which primarily sources, blends, and distributes SAF in addition to developing projects – also has a SAF Book & Claim platform called Fly on SAF, based on Chooose’s SAF program platform.
- World Fuel Services myWorld Decarbonize: Launched earlier this week, the application is said to streamline purchases of SAF via Book and Claim by providing a "simplified way to calculate carbon emissions associated with fuel burn and purchase SAF Certificates (SAFc)."
- Other services: In addition to the platforms above, several airlines have their own SAF programmes, such as DHL’s GoGreen Plus solution.
These services all operate slightly differently, but they address three basic needs:
- Emissions accounting: They must present the environmental benefits of SAF batches: GHG emissions reductions, usually expressed as the difference between baseline life cycle GHG emissions of fossil jet fuel and the adjusted life cycle assessment value of the neat SAF.
- Keeping consistent records: The main goal of registries is to provide a standardised and secure database that allows the issuance, transfer, and retirement of fully traceable SAF certificates. It should also do so while preventing double-counting, which is why interoperability is a growing need for existing registries.
- Emissions reporting: Registries must follow GHG reporting convention set by the Greenhouse Gas Protocol (GHGP) and Science Based Targets initiative (SBTi), so that users can align their SAF inset sales and purchases with internationally recognised standards.
Demand drivers
A look across the 20-plus SAF production facilities operational today around the world shows some overlap with locations or end-markets that have SAF demand policies as well as logistical infrastructure for sourcing feedstock and distribute the end-product. However, non-mandated SAF voluntary demand by airlines and corporates extends far beyond these locations, making SAF Book and Claim registries an ideal channel for producers.
“We are now delivering all of our product, the environmental attributes, via digital registries,” explains Adam Klauber, VP sustainability and digital supply chain at World Energy, the world’s first commercial-scale producer of SAF and one of the largest SAF producers in North America. “Through book and claim, we can deliver to the closest airport to our production facility, which is Los Angeles International (LAX), and reduce the cost to our customers and simplify the logistics,” Klauber explains.
Airlines may purchase SAF from World Energy via the two SAF registries it partners with (RSB Book & Claim Registry and the SABA/RMI SAF-c registry) to address their Scope 1 (direct emissions) regardless of whether they are flying from LAX airport. Corporate customers purchase the environmental attributes via SAF certificates to apply against Scope 3 (indirect) emissions, regardless of where those emissions occur.
Interoperability
SAF Book & Claim registries in operation today were designed to address the needs of an initial set of customers. As a result, each registry takes a different accounting approach to SAF batches and their environmental attributes. Klauber notes that some – like the RSB and SAF-c registry – have become more similar overtime, for instance by unbundling the Scope 1 and Scope 3 environmental claims into separate certificates (a feature SAF-c had, and RSB later added). Nevertheless, separate registries increase the risk of double-issuance, which could result in one SAF batch being listed on multiple registries.
Klauber, who also chairs RSB’s board, sees two options to overcome this: registries communicating with each other – which he deems “difficult” – or being overseen by an issuing body, which would act as an initial clearing authority before book and claim units are logged into registries. “[An issuing body] doesn't exist yet, but it is a model from wind and solar, and the wind and solar markets have shown that that's been an effective way to eliminate the possibility for double issuance,” he explains.
These solutions are being considered by a joint industry group: the ISEAL Interoperability Project. The project, launched in May 2024, is coordinated by RSB and founded by grants from Swiss-supported ISEAL Innovations Fund. According to Klauber, registries participating in the project aim to launch an interoperability pilot in Q2 2025. Despite these efforts by registries participating in the project, of which IATA is a member, the airline association has taken proactive steps to develop interoperability.
Michael Schneider, assistant director aviation environment at IATA, explains that having a top-down approach with a ‘watchtower’ issuing body proves “very difficult, if not impossible” due to funding questions and the need to balance the interests of many stakeholders. “So, we thought maybe we should have a different take on this and have more of a bottom-up approach.” Following Ishka's interview, on 24th March IATA announced that its SAF Registry is to be operated by a non-for-profit organisation incorporated in Canada of which IATA is the founding member - the Civil Aviation Decarbonisation Organization (CADO).
The IATA SAF registry
The IATA SAF Registry, due to be launched in April, will build on the IATA SAF Accounting and Reporting Methodology published earlier this year, a framework for airlines and other value chain actors setting forth a “rulebook” to account for SAF and its environmental benefits. With the methodology, IATA wants to enable airlines to consistently account for the SAF that they are choosing to use under regulated or voluntary frameworks – from ReFuelEU Aviation (a SAF mandate that falls on fuel suppliers) to CORSIA, where international airlines can opt to use CORSIA-eligible SAF and low-carbon fuels to offset above-baseline emissions instead of carbon credits.
IATA acknowledges that a range of SAF Book & Claim registries already exist and for its proposition to hold up it must have key differentiators.
Interoperability
IATA says it has drawn inspiration from the US’ Renewable Energy Certificates (RECs) system, in which data is exchanged between registries via an API to detect and prevent double issuance. IATA says it has proposed to other registries to work on this basis, and that offer led to the recent collaboration agreement with 123Carbon, a carbon insetting platform. “We are going to offer this interoperability day one when the IATA SAF Registry goes live[…] We felt, let’s start with one registry […] we need to demonstrate to everyone out there that it can be done,” explains Schneider.
Government relations
In addition to its industry-first interoperability initiative with 123Carbon, IATA will work with governments to accommodate and facilitate regulatory considerations. “You need to have a common way and a global and harmonised way on how we account for the benefits of that SAF,” comments Schneider.
“We will have governments being part of this, having their own accounts, being able to receive information in front of them, so they can validate claims and even accept claims, or create outputs.” IATA sees “numerous” possible uses by governments, such as maintaining an inventory of emissions, or for European countries to supplement the Union Database for Biofuels (UDB).
Airline-centric
Schneider also describes the IATA SAF Registry as “airline-centric,” putting a greater emphasis on SAF certification to allocate value rather than feedstock preferences, as it’s not for IATA “to judge” what is good or bad SAF. “We would rather focus on the transparency aspects.”
Setting some expectations ahead of its launch, Schneider notes that IATA is in discussions with “more than 10 states,” “40 plus airlines,” and “more than 30” fuel suppliers in preparation for the registry’s launch. The system will be offered free of charge for the first two years to create a meaningful userbase and it will be open to non-IATA members. It will then move into a “cost recovery” phase but being mindful of keeping “costs down” for the benefit of airlines. Unlike commercially-driven SAF Book & Claim system developers, IATA says it has “no commercial interest.”
Other barriers to adoption: GHGP and SBTi recognition
Lastly, another barrier facing wider SAF Book & Claim adoption are SAF accounting standards for corporates. While some large corporates, such as members of the Sustainable Aviation Buyers Fuel (SABA) alliance, have developed their own way of including SAF credits in their emissions accounting, others are reluctant to take the step without clearer guidance.
One of those barriers is the Greenhouse Gas Protocol (GHGP), a global standardised framework for measuring and managing greenhouse gas emissions. It is the framework that helps companies categorise emissions into Scopes 1, 2, and 3. Since its publication in 2004, further guidance has been added to the GHGP to take into account, for instance, the market-based method of purchasing electricity. Further guidance is needed to account for “new market-based approaches”, including SAF. A final cross-sectoral “standard and/or guidance” on these is currently estimated to be finalised by Q4 2028.
“We don’t know what the end deliverable will look like, but it should come in the form of an explicit guidance document or standards,” explains Azim Norazmi, climate policy manager at IATA. “This is something we can’t wait for to have clarity,” adds Norazmi. In the meantime, IATA would like to work with the GHGP to urge “clarity” in the form of an “interim document or statements” that would operationalise SAF Scope 1 and Scope 3 attributes.
That deliverable will be cross-sectoral and will likely extend beyond SAF. Until that guidance comes through, SAF Book & Claim demand – particularly by corporate customers – is likely to remain limited to companies adapting their own emissions accounting, like the SABA members.
Another barrier is the Science Based Targets initiative (SBTi), which guides corporate environmental target-setting. Guidance issued in 2021 by SBTi for aviation makes some recommendations on corporate use of SAF to meet SBTi Scope 3 targets, but it notes that the “use of SAF certificates traded on a marketplace/exchange or carbon credits/offsets cannot at this time be counted towards a science-based target due to potential inconsistencies with GHG protocol guidance.” In mid-March, SBTi published an initial 133-page draft of its revised Corporate Net-Zero Standard for public consultation which acknowledges that, in some circumstances, “indirect mitigation as a time-limited measure” can help address indirect emissions and notes as an example "SAF following a book-and-claim” approach.
As an interim solution until the GHGP develops guidance, Klauber proposes other bodies step up. “It could be some interim tool that then could be absorbed by CDP [another non-profit supporting corporate environmental disclosure] or recognised officially by SBTi, or potentially they could build their own, but we do need some way for companies to say ‘look, we used these many SAF certificates, and therefore we could take this away from our aviation emissions’.”
The Ishka View
Another benefit of SAF Book and Claim may be enabling better demand signals for SAF projects that could ultimately make them bankable and guarantee project execution. RSB and World Energy are currently working on a ‘Demand Signal Recognition Book and Claim Pilot’ which seeks to develop and test a new methodology and verification system to demonstrate bankable demand signals in SAF transactions. Definitive emissions reporting guidance on SAF Book and Claim is also something that, while it may take months if not years to complete, other initiatives may be able to mitigate in the shorter term. This could be done via interim guidance by GHGP or SBTi, but also by coordinating reporting alignment between companies, something that RMI and the Smart Freight Centre are aiming to do via the SAF Book and Claim Community established last September.
IATA’s SAF Registry holds promise, but the association still appears to have some minds to win among SAF producers, some of whom prefer the unbundling of Scope 1 and Scope 3 certificates – which other SAF registries prioritise but IATA’s seemingly will not. Some SAF producers prefer this unbundling as it maximises commercial flexibility, allowing them to more effectively address voluntary SAF demand from corporates. But that sentiment is not universal, and IATA highlights that its upcoming registry will be supported by at least 15 fuel producers.
Update: As Ishka goes to press, Airbus had just announced a SAF Book and Claim trial, including the signing of MoUs with SMBC Aviation Capital, followed by AerCap, Comlux, Luxaviation, Novespace, Rive Private Investment and SAF Aerogroup. Through a pilot programme running throughout 2025, Airbus will purchase SAF certificates and manage the associated sustainability attributes through the RSB Registry. These certificates will then be resold to interested customers.
